Auditory context effects in picture naming investigated with event-related fMRI.

Full Abstract

Naming an object entails a number of processing stages, including retrieval of a target lexical concept and encoding of its phonological word form. We investigated these stages using the picture-word interference task in an fMRI experiment. Participants named target pictures in the presence of auditorily presented semantically related, phonologically related, or unrelated distractor words or in isolation. We observed BOLD signal changes in left-hemisphere regions associated with lexical-conceptual and phonological processing, including the mid-to-posterior lateral temporal cortex. However, these BOLD responses manifested as signal reductions for all distractor conditions relative to naming alone. Compared with unrelated words, phonologically related distractors showed further signal reductions, whereas only the pars orbitalis of the left inferior frontal cortex showed a selective reduction in response in the semantic condition. We interpret these findings as indicating that the word forms of lexical competitors are phonologically encoded and that competition during lexical selection is reduced by phonologically related distractors. Since the extended nature of auditory presentation requires a large portion of a word to be presented before its meaning is accessed, we attribute the BOLD signal reductions observed for semantically related and unrelated words to lateral inhibition mechanisms engaged after target name selection has occurred, as has been proposed in some production models.

Author information

Author/s: de Zubicaray, Greig I (GI); McMahon, Katie L (KL);

Affiliation: University of Queensland, Brisbane, Queensland, Australia. greig.dezubicaray(-atsign-)uq.edu.au

Journal and publication information

Publication Type: Journal Article

Journal: Cognitive, affective & behavioral neuroscience (Cogn Affect Behav Neurosci), published in United States. (Language: eng)

Reference: 2009-Sep; vol 9 (issue 3) : pp 260-9

Dates: Created 2009/08/14; Completed 2009/10/26;

PMID: 19679762, status: MEDLINE (last retrieval date: 10/26/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article
(including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.